Article

Early Hominid Diets from Quantitative Image Analysis of Dental Microwear

Duke University, Durham, North Carolina, United States
Nature (Impact Factor: 41.46). 07/1988; 333(6175):765-8. DOI: 10.1038/333765a0
Source: PubMed

ABSTRACT

The dietary habits of the early hominids Australopithecus and Paranthropus have long been debated. Robinson argued that the two species differed in the proportions of meat and vegetables consumed. More recently it has been suggested that Paranthropus, with its presumably larger body size, simply processed greater amounts of the same foods eaten by Australopithecus to maintain 'functional equivalence'. Microscopic dental wear patterns are related to the dietary habits of extant mammals, and quantification of these patterns is useful in distinguishing among primates with different diets. Nevertheless, few attempts have been made to use microwear in the reconstruction of early hominid diets, and only very recently has the quantification of such data been initiated. While microwear fabrics can be reduced to individual elements (for example, scratches and pits), there is some disagreement over exactly how they should be defined and measured. Fourier transforms have been applied successfully in the study of a variety of physical and biological patterns, and recently they have been used to characterize and distinguish different tooth wear patterns more objectively. Here we report the first combined use of image processing and other quantitative techniques to analyse the dental microwear of early hominids. Our results suggest that Paranthropus ate substantially more hard food items than Australopithecus.

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Available from: Richard F. Kay, Apr 18, 2015
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    • "The main aim of this research is to comparatively assess the evolutionary changes, biogeographic habitats, and dietary habits of the above-mentioned suid species, following methodologies of morphometric systematics, tooth microwear (Solounias and Semprebon, 2002) and statistical analysis mainly on the dentognathic specimens. The study of tooth wear on extinct and extant mammal species is significant in the interpretation of diets and ecological reconstructions following pioneering works of a number of researchers (Walker, 1976; Walker et al., 1978; Ryan, 1981; Rose, 1983; Grine, 1986 Grine, , 1987 Grine and Kay, 1988; Teaford and Oyen, 1989; Teaford and Robinson, 1989; Ungar, 1994 Ungar, , 1996 Ungar and Teaford, 1996; Solounias and Semprebon, 2002; Rivals et al., 2008; Teaford, 2007; Rivals et al., 2009; Solounias et al., 2010). Rapid speciation in suids and adaptations have been studied from the point of view of their dental morphology, stable isotope composition (Harris and Cerling, 2002 ), and postcranial anatomy (Bishop, 1994Bishop, , 1999 ). "
    [Show abstract] [Hide abstract] ABSTRACT: The fossiliferous late Early Pleistocene deposits of the Buia Basin (dated to c. 1Ma) at the Danakil depression, contain three different suid species (Kolpochoerus olduvaiensis, Kolpochoerus majus, and Metridiochoerus modestus).These suid taxa are morphologically evolved and are found in association with a diverse large vertebrate faunal assemblage, including the genus Homoand a rich accumulation of Acheulean tools. The anatomic, biometric,morphometric and dental microwear analyses, showsignificant data of dietary traits, habitat and evolutionary changes. In suids, despite their omnivorous diets, microwear study can play a significant role in understanding dietary habits. The results of our study show morphological distinction between the three suid species. Conversely, the microwear patterns recorded on the dental surfaces show overlapping of ecological niches among the species. We believe that their opportunistic feeding and rapid reproduction process might have sustained their survival within the mosaic environments of the Buia Basin in competition with other faunas (other ungulates, carnivores and monkeys) and hominins.
    Full-text · Article · Apr 2015 · Palaeogeography Palaeoclimatology Palaeoecology
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    • "Microwear, the analysis of microscopic tooth wear, has been widely used as a method of paleoecological reconstruction (Grine, 1986; Grine and Kay, 1988; Solounias et al., 1988 Solounias et al., , 2010 Solounias and Semprebon, 2002; Merceron et al., 2004 Merceron et al., , 2005 Fraser and Theodor, 2013) and determining selective forces (e.g. climate and diet factors) responsible for various mammalian adaptations (e.g. "
    [Show abstract] [Hide abstract] ABSTRACT: Microwear, the quantification of microscopic scratches and pits on the occlusal surfaces of tooth enamel, is a commonly used as a paleodietary proxy. For ungulates (hoofed mammals), scratch-dominant microwear distinguishes modern grazers from browsers, presumably as a result of abrasion from grass phytoliths (biogenic silica). However, it is also likely that exogenous grit (i.e., soil, dust) is a contributing factor to these scratch-dominant patterns, which may reflect soil ingestion that varies with feeding height and/or environmental conditions (e.g., dust production in open and/or arid habitats). This study assesses the contribution of exogenous grit to tooth wear by measuring the effects of fine- and medium-grained silica sand on tooth enamel using a novel live animal tooth molding technique. This study therefore constitutes the first controlled feeding experiment using ungulates and the first in vivo experiments using abrasives of different sizes. Four sheep were fed three diet treatments: 1) a mixture of Garrison and Brome hay (control), 2) hay treated with fine-grained silica sand (180-250 µm), and 3) hay treated with medium-grained silica sand (250-425 µm). We found a significant increase in pit features that was correlated with an increase in grain size of grit, corroborating earlier chewing simulation experiments that produced pits through grit-induced abrasion (i.e., the 'grit effect'). Our results support an interpretation of large silica grains fracturing to create smaller, more abundant angular particles capable of abrasion, with jaw movement defining feature shape (i.e., scratch or pit). © 2015. Published by The Company of Biologists Ltd.
    Full-text · Article · Apr 2015 · Journal of Experimental Biology
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    • "Conventional wisdom has it that hard foods are fractured in compression (normal, axial loading), leaving residual pits on the enamel surface, whereas soft foods are ground down in shear (sliding , translational loading), leaving scratches. Individual microcontact signals typically occur on a width scale of 1–20 lm [5] [7]. The ratio of pits to scratches is taken as a measure of diet: some teeth show either scratches or pits, suggesting specialist diets; others show both scratches and pits, suggesting more omnivorous diets. "
    [Show abstract] [Hide abstract] ABSTRACT: We hypothesize that microwear traces in natural tooth enamel can be simulated and quantified using microindentation mechanics. Microcontacts associated with particulates in the oral wear medium are modeled as sharp indenters with fixed semi-apical angle. Distinction is made between markings from static contacts ('pits') and translational contacts ('scratches'). Relations for the forces required to produce contacts of given dimensions are derived, with particle angularity and compliance specifically taken into account so as to distinguish between different abrasives in food sources. Images of patterns made on human enamel with sharp indenters in axial and sliding loading are correlated with theoretical predictions. Special attention is given to threshold conditions for transition from a microplasticity to a microcracking mode, corresponding to 'mild' and 'severe' wear domains. It is demonstrated that the typical microwear trace is generated at loads on the order of 1 N-i.e. much less than the forces exerted in normal biting-attesting to the susceptibility of teeth to wear in everyday mastication, especially in diets with sharp, hard, and large inclusive intrinsic or extraneous particulates. Copyright © 2014. Published by Elsevier Ltd.
    Full-text · Article · Dec 2014 · Acta Biomaterialia
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